1. Field of the Invention
The present invention relates to a method for producing an organic field-effect transistor.
2. Description of the Related Art
In the field of microelectronics there is a constant need to develop smaller device elements that can be reproduced conveniently and inexpensively at a lowest possible failure rate. Modern digital integrated circuits are based on field-effect transistors (FET), which rely on an electric field to control the conductivity of a “channel” in a semiconductor material. Organic field-effect transistors (OFET) allow the production of flexible or unbreakable substrates for integrated circuits having large active areas. As OFETs enable the production of complex circuits, they have a wide area of potential application (e.g. in driver circuits of pixel displays).
Methods for the manufacture of integrated circuits (IC) are well known in the art, e.g. by lithographic techniques.
DE-A-32 35 526 discloses perylene-3,4,9,10-tetracarboxylic diimides, which are substituted on the perylene nucleus with at least one group selected from among alkoxy, alkylthio, aryloxy, arylthio, ═SO2 and —SO2—R groups. In addition, they may be substituted on the perylene nucleus with at least one chlorine or bromine group.
DE-A-34 34 059 discloses chlorinated perylenetetracarboxylic diimides prepared by chlorinating perylenetetracarboxylic diimides with sulfuryl chloride in an inert organic liquid in the presence of a catalyst. The perylene nucleus bears 2, 3, 4 or 5 or 6 chlorine groups. The substituents of the diimide nitrogen atoms are, independently of one another, either a) straight-chain or branched C1-C18-alkyl which is unsubstituted or substituted by cyano, hydroxyl, cycloalkyl, alkylcarbonyloxy, alkenylcarbonyloxy or cycloalkylcarbonyloxy and in which the alkyl chain may also be interrupted by O or S, or b) C5-C18-cycloalkyl, which is unsubstituted or substituted by alkyl, carboalkoxy or trifluoromethyl.
DE-A-195 47 209 discloses 1,7-disubstituted perylene-3,4,9,10-tetracarboxylic dianhydrides and perylene-3,4,9,10-tetracarboxylic acids where the substituents are selected from among substituted or unsubstituted aryloxy, arylthio, hetaryloxy or hetarylthio. Also disclosed are 1,7-dibromoperylene-3,4,9,10-tetracarboxylic diimides as intermediates for these compounds.
U.S. Pat. No. 5,986,099 discloses substituted quaterrylenetetracarboxylic diimides, wherein the aromatic nucleus can bear up to 12 substituents, inter alia halogen.
US 2005/0222416 A1 discloses 1,6,9,14-tetrasubstituted terylentetracarboxylic diimides wherein the substituents are inter alia bromine.
DE-A-101 48 172 describes fluorescent 2,6-substituted naphthalene-1,4,5,8-tetracarboxylic diimides, wherein the substituents are independently hydrogen, halogen, amino, —NHR or —OR, at least one of the substituents being different from hydrogen or halogen. Also disclosed are 2,6-dichloro-naphthalene-1,4,5,8-tetracarboxylic diimide and 2,6-dibromo-naphthalene-1,4,5,8-tetracarboxylic diimide that are employed as intermediates. The disclosed naphthalene-1,4,5,8-tetracarboxylic diimides are used inter alia as fluorescent dyes and laser dyes.
H. Langhals and S. Kirner disclose in Eur. J. Org. Chem. 2000, 365-380 fluorescent dyes on the basis of core-extended perylenetetracarboxylic bisimides. The only concrete halogen-substituted compound disclosed is 1-bromo-N,N′-bis(1-hexylheptyl)perylene-3,4,9,10-bis(dicarboximide).
H. Tian discloses in Tet. Let. 46, 2005, 4443-4447 the bromination of perylenetetracarboxylicbisanhdride yielding the tetrabromo derivative. Regarding the corresponding tetrabromodiimide no isolation and characterization is described.
D. Zhu discloses in Org. Let. 2006, 8, 5, 867 the corresponding tetrabromoperylenediimide with ethylhexyl substituents.
None of the aforementioned literature references describes the use of derivatives of rylene tetracarboxylic acids as n-type organic semiconductors for the production of OFETs.
M. J. Ahrens, M. J. Fuller and M. R. Wasielewski, Chem. Mater. 2003, 15, pages 2684-2686, disclose cyanated perylene-3,4-dicarboximides and perylene-3,4,9,10-bis(dicarboximide) as facile chromophoric oxidants for organic photonics and electronics.
B. A. Jones et al., Angew. Chem. 2004, 116, pages 6523-6526, describes dicyano-perylene-3,4,9,10-bis(dicarboximides) as high-mobility air-stable n-type semiconductors.
US 2005/0176970 A1 discloses the use of perylene-3,4-dicarboximides and perylene-3,4,9,10-bis(dicarboximide) with one or more electron-withdrawing moieties or groups as n-type semiconductors. Compounds with bromine substituents on the perylene nucleus are only employed as intermediates in the synthesis of the target molecules.
The compounds employed as n-type semiconductors according to the three last-mentioned literature documents do not bear halogen substituents.
Chem Phys Chem 2004, 5, 137-140 describes studies on structural, electrochemical and charge transport properties of tetrachloro-substituted perylene bisimides of the formula
where R=n-C12H25, 4-(n-C12H25)C6H4, 2,6-(i-C3H7)2C6H3. This document does not teach a method for the production of OFETs.
J. Mater. Chem., 2005, 15, 1270-1276 (Wuerthner, Muellen et al.), reports on an increase in charge carrier lifetime in a liquid crystalline perylene bisimide derivative upon substitution of the aromatic nucleus with chlorine. The employed perylene bisimide derivative has the following structure

This document also does not teach a method for the production of OFETs.
US 2005/0017237 describes electronic devices including a semiconductor layer on the basis of compounds of the rylene type. The only concrete example of a thin film transistor comprises a perylenetetracarboxylic diimide with unsubstituted aromatic core.
US 2003/0181721 A1 (Wuerthner) discloses tetra-substituted perylenetetracarboxylic diimides of the formula
where    R1, R2, R3 and R4 are independently hydrogen, chlorine, bromine, substituted or unsubstituted aryloxy, arylthio, arylamino, hetaryloxy or hetarylthio,    R5, R6, R7, R8, R9 and R10 are independently hydrogen or long-chain alkyl, alkoxy or alkylthio with the proviso that at least four of these radicals are not hydrogen.
It is also mentioned in very general terms that such perylimides are useful for electronics, optoelectronics and photonic applications such as charge transport materials in luminescent diodes and photovoltaic diodes, photoconductors and transistors. This document also does not teach a method for the production of OFETs. The only concrete halogen-substituted compounds disclosed have aromatic nuclei substituted by four chlorine radicals or four bromine radicals and they are only used as intermediates in the synthesis of the target molecules.
D. Schlettwein et al compares in Organic Electronics 5 (2004), 237-249 the electrical properties of thin films of 1,6,7,12-tetrachloro-N,N′-dimethylperylene-3,4,9,10-biscarboximide prepared by physical vapour deposition with those of the corresponding unchlorinated compound. The specific conductivity of thin films of the unchlorinated substrate is about 100 times higher than that of the unchlorinated compound.